Darius Guppy, the convicted fraudster who once sought Boris Johnson's help in a plot to beat up a journalist, has launched a libel action over claims that he has become a stooge of the Iranian regime. Guppy achieved notoriety in 1993 when he was jailed for an £1.8m insurance fraud involving a faked robbery. Guppy, best man to Earl Spencer, asked his friend Mr Johnson to give him the address of a journalist investigating the case, so that he could have him beaten up.

First it was Roman versus Boris. Next up it is Oleg against Mikhail. The curtain will be raised in the High Court this week on the latest multibillion-pound dog-fight between oligarchs – this time over the ownership of the world's biggest aluminium company.

Faced with slowing growth in its advertising business, Facebook is considering throwing open its social network to children, in the hope that their parents will pay for games and other content on the site.

Outlook Yell has a problem. The stumbling directories business that used to be known as Yellow Pages has become a byword for bad management and bad debt. (It has a mountain of the stuff which needs restructuring. Again.) Not to mention the fact that the internet has presented all sorts of challenges to its business model.

Failures by police and prosecutors to disclose evidence and handle “supergrass” witnesses led to the collapse of a trial of three men accused of committing one of Britain’s most notorious unsolved murders.